Load sensitive fuel governor for gas turbines



March 9, 1954 J. E.. BEvlNs LOAD SENSITIVE FUEL GOVERNOR FOR GAS TURBIES Filed June 26, 1947 EXCITOR ALTERNATOR 2 Sheets-Sheet l FUEL INPUT ILV OIL INPUT LuaolL FOR TuRBlNE MECHANISM- INVENTOR.

March 9,l 1954 J. E. BEvlNs 2,671,860v

LOAD SENSITIVE FUEL GOVERNOR FOR GAS TURBINES Filed June 26, 1947 47FUEL TO NOZZLE 2 Sheets-Sheet 2 INLET PRESS.

o IK l FUEL OUTLET LUBRICAT ION IL SUPPLY INVEN TOR.

M1755 E. BE w/v5 BY v Patented Mar. 9, 1954 LOAD SENSITIVE FUEL GOVERNOR FOR GAS TURBINES- James Emil Bevins, Ramsey, N. J., assigner to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application June 26, 1947, Serial No. 757,109

(Cl. 29o- 40) 23 claims. l

The present application relates to a load sensitive fuel :regulator system .and governor for a gas turbine drive.

An object of the invention is to provide a regulator or governor to rkeep the .air-fuel ratio of a gas turbine at a safe minimum and .to make the control sensitive to the electrical load applied to a generator driven by the turbine.

Another object of the invention is to provide an overspeed trip acting independently of the governing means and arranged to yshut off inlet fuel to the turbine under excessive speed conditions and which trip may be manually reset.

Another object of the invention is to provide a .combination fuel and oil pump driven by the turbine for supplying oil for .operating the regulator and fluid fuel for .the turbine.

Another object of .the invention is to provide a governor system for a gas turbine in which the basic control is speed which is put into the system by a centrifugal .governor driven by the turbine through .the fuel and .oil pump and in which the governor operates a lever which in turn operates a pilot valve .so as to .control a throttling valve in the fuel supply line for .the turbine.

Another object of the invention is to provide in the latter system means to prevent hunting in the form of a load sensitive solenoid which acts as a movable fulcrum for the lever aforenoted and resets the governor to a lower speed for increased load. The action of the solenoid is to provide a predetermined droop in the speed curve with increasing load and 4it is considered that a five percent droop from zero to one hundred percent load will effectively stabilize the system.

Another object of the yinvention is to provide a novel control piston positioned by the servo oil pressure so as to vvary fuel flow to the nozzle of the turbine in response to Aa governor driven from the drive shaft of the turbine and control- 4ling a pilot valve.

Unless suitable means is provided to protect `the lgas turbine during accelerating cycles and periods of overload the governor may adjust the fuel throttle so -as to cause 'the gas turbine to overheat due to the `air-fuel ratio falling below -a safe minimum. 'Therefore another object of vthe invention is to provide an overspecd diaphragm sensitive to the difference Vbetween nozzle fuel pressure and compressor air pressure to override the system and control the fuel throttle so Ithat the air-fuel ratio is held to a safe minimum.

A further object of the invention is to provide an auxiliary overspeed governor arranged to cut ofi the supply of servo oi-l and mechanically close the main fuel inlet valve upon failure'of the gov- -erning system or upon the 'speed of the turbine exceeding -a predetermined safe rate.

The above and other objects and features of the Vinvention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawings wherein one embodiment of the invention is illustrated by way of example.

In the drawings:

Figure 1 is a schematic illustration of a gas turbine system to which the novel regulator may be applied.

Figure 21s a schematic illustration of theregulator.

Referring to Figure l, there is shown a typical gas turbine system to which the novel regulator may be applied and including a compressor I driven through shaft 2 by the turbine 3. vThe turbine 3 has an air inlet 4 and air outlet p assages 5 leading through suitable eXpanSiQn chambers 6 to the turbine 3. The expansion chambers 6 are heated by suitable nozzles `I supplies with fuel by conduits 8.

The shaft 2 is arranged to .drive an alternator 3 having an exciter IB also driven Vby shaft 2. The output of the exciter I0 is connected by lines II and vl2 across the field, not shown, of the alternator 9 in a conventional manner. `'lhe .011tput of the alternator 9 is indicated by lines I3.

The foregoing gas turbine .and generator system may be of conventional design and therefore a further detail description thereof is not deemed necessary.

Fuel-regulator system and governor The novel feature of the invention resides in the fuel regulator and governor indicated generally in Figure 1 by the numeral I4 and shown schematically in Figure 2.

In the latter arrangement there is provided a combination oil and fuel pump indicated generally by the numeral I5.

The combination oil and fuel pump I5 may be of a rotating eccentric type driven b y shaft I-S, shown in Figure 1, from the turbine drive shaft 2. As shown in Figure 2, the pump may include fuel pistons II and oil pistons I8 which are reciprocated by an eccentric I9 mounted on ball bearings 2t and driven by shaft I6.

Suitable connections are made so that shoes 2| transmit the load from the pumping eccentric I9 lto the pistons I1 and I8. Fuel is supplied by a conduit 25 to the cylinder of the fuel pump at the bottom of the suction stroke of the pistons Il and is discharged through ap valves 26 at the ends of the fuel cylinders. Similarly, oil is supplied by conduits 21 to .the cylinder of the oil pump at the bottom of the suction stroke of the pistons I8 and is discharged through nap valves 28 at the ends of the oil cylinders. The oil pumped by the pistons I8, supplies lubrication for the main gas turbine .engine shown `in VFigure -1 and `also for operating the servo system of 4the regulator Ill.

The basic control of the regulator is speed, which is put into the system by a centrifugal governor indicated generally by the numeral 30 and driven by shaft 3| connected to the drive shaft of the pump |5 and through shaft I6 to the main drive shaft of the gas turbine engine shown in Figure 1. The governor 30 may be of a conventional fly ball type and is arranged to operate actuating pin 32, adjusting the position of a lever 33. The lever 33 is pivotally connected at 34 to an adjustable fulcrum pin 35 biased by spring 36 and controlled by electromagnet 31 as will be explained hereinafter. The opposite end of the lever 33 is biased by a spring 38 into contacting relation with the actuating pin 32. Positioned intermediate the opposite ends of the lever 33 is a valve pin 39 biased into contacting relation with the lever 33 by a spring 40. The valve pin 39 controls the operation of a throttling valve indicated generally by the numeral 4|.

Fuel pressure lines 42 lead from the fuel pump previously described to openings 43 in the fuel throttling valve 4|. The throttling valve 4| includes valve portions 44 and 45 which are connected by a stem portion 46. Fuel outlet opening 41 leads from the throttling valve 4| to a conduit 8 leading to the nozzles 1 of the turbine engine shown in Figure 1. Also leading from the throttling valve 4| are by-pass openings 48 connected to conduit 49 which returns excess fuel to a fuel supply tank. The valve portion `45 controls the by-pass openings 48 of the throttling valve 4| so that as the throttling valve moves upward, the by-pass openings 48 are closed, increasing the fuel supply to the nozzle 1 and as the throttling valve 4| moves downward, the by-pass valves are further opened, decreasing the supply fuel to the nozzle line 8.

The operation of the fuel throttling valve 4| is controlled by oil pressure supplied by the pumping pistons I8 through pressure line 50. The pressure line 50 opens into a chamber 5| immediately above the valve portion 44 of the throttling valve 4|. A second line 52 leads from the chamber 5| through a restriction 53 to a valve chamber 54, controlled by the valve pin 39.

The valve chamber 54 is connected through a passage 55 to a pressure chamber 56 immediately below the valve portion 45 of the throttling valve 4|. The valve 39 controls by-pass passage 51 leading from the valve chamber 54 to oil drain 58. The surface area of the valve portion 45 is subject to the pressure in the chamber 56 and has a considerably greater surface area than that of the valve portion 44 which is subject to the pressure in the chamber 5|. It will be seen then that upon the valve pin 39 closing the outlet port 51, as upon the speed of the fly ball mechchanism 39 decreasing below a predetermined value, a pressure will be built up in the chamber 56 exceeding that in the chamber 5| and tending tobias throttling valve 4| in an upward direction so as to further close the by-pass valve ports 48 and increasing the supply of fuel to the nozzle line 8.

However, upon the speed of the fly ball mechanism 30 increasing above a predetermined value, the lever 30 will be actuated in a counterclockwise direction so as to cause valve pin 39 to open the by-pass passage 51 causing a relative increase in the pressure built up in the chamber 5| to be effected due to a resulting increase in the pressure drop across the restriction sa in the conduit 52. In the latter event, the

4 throttling valve 4| will be biased downward, tending to open the by-pass ports 48 so as to decrease the supply of fuel to the nozzle line 8.

It will be seen then that as the speed of the turbine exceeds a predetermined value, the supply of fuel to the nozzle line 8 will be decreased and upon the speed of the turbine mechanism decreasing below a `fpredetermined value, the fuel supplied to the nozzle line 8 will be increased so as to bring the speed of the turbine to the predetermined value.

As shown schematically in Figure 2, outlet lines 60 lead from the oil pistons |8 for supplying lubricating oil tothe main turbine engine. Also, lines 6| lead from the pumping piston |8 for lubricating the fuel pistons |1.

The current in the line I2 from the exciter I0 to the field winding of the alternator 9 is regulated in a conventional manner through operation of a voltage regulator which may be of a suitable type well known in the art. The voltage regulator may be mounted in the alternator 9 and arranged so as to respond to the output voltage across the lines |3 of the alternator 9 to regulate the excitation of the field winding of the alternator 9 so as to maintain the voltage across the lines I3 substantially constant under varying load conditions. Thus the voltage regulator will effect an increase in the field current supplied through line |2 to the alternator 9 with decrease in the output voltage resulting upon an increase in the applied load and will further effect a decrease in the field current supplied through line |2 with increase in the output voltage resulting upon a decrease in the applied load.

In order to prevent hunting, the solenoid 31 is connected by lines 64 and 65 across a shunt resistor 66 connected in line |2 leading from the exciter to the field of the alternator 9 as shown in Figure 1. Thus, the solenoid 31 is responsive to changes in the load on the alternator 9 and tends to bias the movable fulcrum pin 35 downward upon increase in load so as to reset the iiy ball governor mechanism 30 to a lower speed for increased load. The action of the solenoid 31 is to build a predetermined droop into the speed curve with increasing load. It is considered that a five percent (5%) droop from 0 to 100% should stabilize the system during acceleration cycles and periods of overload.

During periods of overload, the fly ball governor 3|) may tend to cause the turbine engine to overheat due to the air fuel ratio falling below a Safe minimum. In order to protect the turbine mechanism from such action, there is provided a bellows 10 connected interiorly to nozzle line 8 through a conduit 1|. A chamber 12 surrounds the bellows 10 and is subjected to the air pressure from the compressor through a conduit 13, as shown in Figures 1 and 2. A spring 14 tends to compress the bellows 13 against the fuel nozzle pressure applied through the line 1|. A pin 15 projects from the bellows 10 actuating the movable fulcrum pin 35. Thus, upon the air fuel ratio decreasing below a safe minimum, the bellows 10 expands, causing the movable fulcrum pin 35 to be biased downward and thereby causing valve pin 39 to open the bypass passage 51 and the fuel throttling valve 4| to decrease the supply of fuel to the line Thus, the bellows 19, sensitive to the difference between nozzle pressure and compressor pressure, overrides the system and controls the valve pin 39 so that the air fuel ratio is held to a safe minimum.

comme@ A centrifugal pump, 'indicated `generally @by the numeral T5 .is built integrally with :the crank .shaftof :the pump le .and supplies pressure which is proportional :to the speedof the turbine mec`h ranism. The centrifugal l.pump 1.5 includes radial passages 1.6 `.which Vlead from a central inlet lpassage ll, indicated lby dotted lines in Figure 2. Oil `under centrifugal force is supplied :the `radial passages .16 :to .an .outlet .chamber 18A `Which is :connected .by .outlet pressure conduit 118 to `one side of .a diaphragm mechanism 71.9. vA `spring T80 acts on the diaphragm in opposition to the latter pressure. The opposite side of the .diaphragm 19 is connected through line -81 'to the inlet oil pressure at the :central ".inlet pas- Asage 11.

The diaphragm 1S operates through -a pin l82 and pivoted .arm 83 .a trip :pin 84 for controlling .a plunger vor valve "85. Thus, when the :centrifugal pressure from the pump l5 exceeds -a safe operating .speed lim-it, 'it overcomes the .spring .Bil in the overspeed trip `diap'lfiragm 3S .and Aa-llovvs plunger 185 biased 'by .a spring vB6 to :be released. The `released Aplunger or valve E5 is :biased by spring 316 into chamber SSI so as -to close oil servo conduit :0 kand cut off the supply 'of servo oil. 'The released plunger 85 further .biases throttli-ng valve' :4l downward so as to mechanically .close the main fuel inlet ports y43. `The 'plunger :8-5 :may be .manually reset by appropriate .adjustment of knob 'iB-l' connected .through a .stem 8.8 to `the vplunger 35. At the Aopposite side of 'the plunger 85 is a second stem 89 slidab'ly mounted in l-a suitable channel SB fformed inthe valve portion M. A drain passage *Bl serves :to permit oil which may seep :into -channel '90 `to :be drained `to the oil Vsupply through a passage 92.

Operation.

There is thus provided a 'regulator and governor in which the `basic control 'is the speed of the turbine machine. yThe speed .of :the `turbine machine is connected into :the system :by Va governor mechanism 3.!! which operates a lever 33 .and thereby a pilot valve 3.9 .to control :the throttling valve 4A! `:"fcr the nozzle rsupply line 8. This latter `action ,is .effected by operation .of l'the pilot valve 39 so that `when the .pilot valve S39 `closes a y-by-pass passage 51, the .pressure builds up in chamber 56 .so ras to :cause the Ithrottling valve `4| to increase the fuel supply. .Opening .of the vpilot :valve .3.9 'causes an Iopposite :eiect and a'decreasedsupply of fuel to the nozzle line il.

In order lto prevent hunting,v a load .sensitive solenoid 31 acts as a movable fulcrurn for the .lever and resets the governor 3l! for .a .lower speed setting upon an 4increase in the loadlon the valternator -9 driven by the turbine machine of `Figure l. The action of the solenoid 33'! is to `provide :a predetermined droop in the speed curve with increasing 'load on 'the lalternator 9 .driven vby the turbine machine.

In order to protect `the turbine machine during `periods of overload fa bellows rnechal'l-isrn 11%, sensitive to the .difference 'between nozzle pres- `sure vand compressor :pressure overrides the system and controls the throttlingvalve `1li-Jl so that the air :fuel ratio is held lto arsate minimum.

A further feature of the .control is .la centrifugal pump iii which is driven from the niain shaft 2 of :the turbine machine and supplies :pressure which .is proportional lto `the :speed :of `the turbine machine to a diaphragm .19. "When lthe centrifugal pressure lexceeds @safe :operating speed limits, it :biases `the diaphragm .19 so as to permit .a spring loaded plunger to be released. This plunger :cuts on :the supply of :servo oil and mechanically vcloses :the main `fuel supply line 8. Opera-tion of :the :mechanism may be reset through a manually :adjustable knob 81.

Although only .one :embodiment of `the invenl'tion .has 'been illustrated and described, various changes in `the form :and .relative .arrangement 'of the parts may be made to .suit requirements.

`What is Aclaimed is:

l. 'The 4combination comprising 4a primemover, an .electric generator and exciter driven by said prime mover, .said exciter connected to `supply current jfor exciting 4said generator, and said generator vconnected to supply power to a variable "load, a speed ygovernor for said .prime mover, electrically operated control means for `adjusting the calibration of said speed governor, means responsive to rvariations in the current suppliedby said exciter to-said generator for affecting said governor .adjusting control .means to provide 'a predetermined droop `in .the speed .setting varying with increasing load, `and the speed of .said prime mover Ebeing controlled simultaneously `by `said governor and by `said control means.

2. The combination defined 'by claim l 'including position-operated means responsive to the adjusted .position -of said governor vand said 'control `means for decreasing the speed of said `prime Vmover vwith increase in load. f

3. A vregulating system for a .prime-mover driven electr-ic generator connected to supply power to .a variable load, comprising ya `speed govyer-nor for said prime mover, .electrically operated control means for adjusting the `calibration of `said speed governor :over `a predetermined range, means responsive to variations in said load for supplying a corrective signal to said governor adjusting control inea-ns to progressively vary the speed vcalibration of said speed governor vover said range, and lposition-operated means responsive to the adjusted position of said Vgovernor Yand said control means for aiiecting the speed of said ypri-me lmover in inverse relation to the load applied to lthe generator.

4. A regulating system vfor a .prime-mover ydriven velectric generator connected to supply power to a Yvariable load, comprising a speed governor 'for said prime mover, electrically opervated control means for vadjusting the 'calibration Lof said speed governor over a predetermined range, means responsive to variations in said load 4for supplying a corrective signal to said governor adiustin-gcontrol means to progressively decrease 'within :said range the speed calibration or said speed governor with increase in the load applied `to the generator and to progressively increase Within said range `the speed Icalibration -of said speed governor with decrease in the load applied l'to the generator.

5. For luse `in a system including acombustion chamber, 'a turbine driven by the exhaust gases from said chamber, a Ycompressor driven by the :turbineiorsupplying air to the-combustion charnfber, fa fuel conduit for supplying a combustible Lfluid to saidfchamber, and agenerator driven by said turbine .and connected to supply power to a :variable iload .the :combination comprising means to regulate' `'the fuel supplied by said conduit to said chamber, a speed governor driven by said turbine, electromag-netically operated control means for adjusting the calibration vof said speed governor over a predetermined range, means 'responsive to'variations in saidload -forsupplying a signal to said control means to provide a predetermined droop in the speed setting progressively varying inversely with the load, and a position operated means responsive to the adjusted position of said governor and said control means to control said regulating means.

6. For use in a system including a combustion chamber, a turbine driven by the exhaust gases from said chamber, a compressor driven by the turbine for supplying air to the combustion chamber, a fuel conduit for supplying a combustible fluid to said chamber, and a generator driven by said turbine and connected to supply power to a variable load; the combination comprising, means to regulate the fuel supplied by said conduit to said chamber, a speed governor driven by said turbine, electromagnetically operated control means for adjusting the calibration of said speed governor, means responsive to variations in said load for supplying a signal to said control means to provide a predetermined droop in the speed setting with increasing load, a floating lever responsive to the adjusted position of said governor and control means to control said regulating means, a diaphragm differentially responsive to the fuel pressure and the compressor outlet pressure to affect said floating lever so as to maintain the air-fuel ratio of the combustion chamber within a safe range during periods of acceleration of the turbine and overload of the generator, a fluid pump driven by the turbine, a differential diaphragm responsive to the inlet and outlet fluid pressures of said pump, and a latch mechanism operated by said diaphragm to cause said regulating means to close the fuel conduit upon the fluid pump outlet pressure exceeding the pump inlet pressure by a predetermined value.

7. For use in a system including a combustion chamber, a turbine driven by the exhaust gases from said chamber, a compressor driven by the turbine for supplying air to the combustion chamber, a fuel conduit for supplying a combustible fluid to said chamber, and a generator driven by said turbine and connected to supply power to a variable load; the combination comprising, means to regulate the fuel supplied by said conduit to said chamber, a speed governor driven by said turbine, electromagnetically operated control means for adjusting the calibration of said speed governor, means responsive to variations in said load for supplying a signal to said control means to provide a predetermined droop in the speed setting with increasing load, a floating lever responsive to the adjusted position of said governor and control means to control said regulating means, and a diaphragm differentially responsive to the fuel pressure and the compressor outlet pressure to aflect said floating lever so as to maintain the air-fuel ratio of the combustion chamber within a safe range during periods of acceleration of the turbine and overload of the generator.

8. Means for controlling the fuel line of an engine, comprising a regulating valve in said line, servo fluid pressure means for operatively positioning said valve, a second valve to control said fluid pressure means, means responsive to speed of said engine, means controlled by said speed responsive means for actuating said regulating valve independently of said fluid pressure means so as to close said fuel line, and a third valve operated by said actuating means to render said fluid pressure means inoperative upon the speed exceeding a predetermined value.

9. Means for controlling the fuel line of an engine, comprising a regulating valve in said line, servo fluid pressure means for operatively positioning said valve, a second valve to control said fluid pressure means, engine overspeed responsive means, a latch mechanism operated by said overspeed responsive means, a, plunger releasably locked by said latch mechanism, a spring eective upon release of said plunger to bias said plunger so as to actuate said regulating valve into a position to close said fuel line so as to terminate operation of the engine upon the speed thereof exceeding a predetermined value, said plunger including an auxiliary valve positioned by said spring so as to render said fluid pressure means inoperative.

10. Means for controlling the fuel line of an engine, comprising a throttling valve in said line, said throttling valve having opposite end portions of different surface areas, conduit means for applying fluid pressure to the opposite end portions of said valve, a restriction in said conduit means between said opposite end portions, one end of said conduit means having an opening to a drain, a pilot valve to control said opening for varying the pressure applied at the one end portion o1' said throttling valve for effecting movement thereof, a governor responsive to an engine condition for controlling said pilot valve. an overriding valve normally opening said conduit means and operable to close said conduit means, an engine overspeed responsive mechanism operating independently of the governor, and biasing means controlled by said mechanism to actuate the throttling valve independently of the fluid pressure so as to close the fuel line and to position the overriding valve so as to close said conduit means upon the speed of the engine exceeding a predetermined value.

11. Means for controlling the fuel line of an engine, comprising a throttling valve in said line, said throttling valve having opposite end portions of different surface areas, conduit means for applying fluid pressure to the opposite end portions of said valve, a restriction in said conduit means between said opposite end portions, one end of said conduit means having an opening to a drain, a pilot valve to control said opening for varying the pressure applied at the one end portion of said throttling valve for effecting movement thereof, a governor responsive to an engine condition for controlling said pilot valve, an overriding valve to control said conduit means, an overspeed responsive means operating in dependently of the governor, a latch mechanism controlled by said overspeed responsive means, said overriding valve releasably locked by said latch mechanism in a position to open said conduit means, a spring to bias said overriding valve and effective upon release of said overriding valve by said latch mechanism to bias said throttling valve into a `position to close said fuel line and to af'l'ect said overriding valve so as to close said conduit means upon the speed of said engine exceeding a predetermined value, and manually operable means for resetting said overriding valve, and latch mechanism.

l2, Apparatus for use in controlling the fuel line of an engine, comprising a throttling valve having opposite end portions of different surface areas and an intermediate portion for controlling said fuel line, a, ilrst conduit for connecting the end portion of smaller surface area directly with a source of fluid pressure and independently of said end portion of larger surface area, a second conduit for connecting said 9.. end portion of largery surface area witn said source of fluid pressure andi having a restriction therein, an opening in said second conduitto drain, a pilot valve controlling saidl opening to vary the pressure applied to the endportion of larger area to effect movement of the throttling valve, and a condition responsive governor adapted to respond to an operating condition` of the engine when connected-` thereto, said governor controlling the operation of said pilot valve.

13. Apparatus for controlling the fuel line of anengine having a supercharger driven thereby for supplying air under pressure to the engine, said apparatus comprising a throttling valve having opposite end portions of different surface areas and an intermediate portion controlling said fuel line, a first conduit connecting the end portion of smaller surfacel area directly With a source of fluid pressure and indepeudenti-yv of said end portion of larger surface area, a second conduit connecting said end portion of larger surface area with said source of fluid' pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve controlling said opening tol vary the pressure applied to the end portion of larger area to effect movement of the throttling valve, an engine speed governor for controlling the operation of said pilot valve, and an auxiliary control device responsive to the difference between the supercharger air pressure andthe fuel pressure in the fuel line of the engine to affect said pilot valve to cause movement of said throttling valve in a closing direction when the fuel pressure exceeds the supercharger air pressure by a predetermined value.

14. Regulating means. for regulating a fuel conduit for a combustion engine; said regulating means comprising a throttling valve having opposite endv portions of different surface areas and an intermediate portion adapted to control said fuel conduit,- a firstk conduit for connecting the end portion of smaller surface area with a source v of fluid pressure and independentlyv of saidl end portion of larger surface area, a' second conduit for connecting said end portion of 'larger surface area With said source of fluid pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve controlling said opening toy vary the pressure applied to the end portion of larger azreal to effect movement of the throttling valve, and a governor operatively connected to said pilot valve, said governor in cluding speed responsive means adapted tol respond to the driven speed ofthe engine when connected thereto for controlling the pilot valve in response to the driven speed of the engine.

15. Regulating means for regulating a fuel conduit for a combustion engine having an inlet conduit; said regulating means comprising a throttling valve' having opposite end portions of different surface areas and an intermediate portion adapted to control said fuel conduit, a first conduit for connecting the end portion ofi .smaller surface area with a source of fluid pressure and independently of said end portionv of larger surface area, a secondY conduit for connecting said end portion of larger surface area with said source of fluid pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve. controlling! said opening to vary the pressure applied tothe end portion of larger `area to effect movementof the throttling valve and a governor operatively connected to said pilot valve, said governor including dif- 10 ferential pressure responsive means adapted to respond to the ratio of the air-fuel mixture supplied the engine, said governor controlling the pilot valve in response to the air-fuel ratio.

16. Regulating means for regulating a fuel conduit for a combustion engine having an air inlet conduit; said. regulating means comprising a throttling valve having opposite end portions of different surface areas and an intermediate portion adapted to control said fuel conduit, a first conduit for connecting the end portion of smaller surface area with a source of fluid pressure and independently of sai-:l end portion of larger surface area, a second conduit for connecting said end portion of larger surface area with said source of fluid pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve controlling said opening to vary the pressure applied to the end portion of larger area to effect movement of the throttling valve, and a governor operatively connected to said pilot valve, said governor including speed responsive means adapted to respond to the driven speed of the engine when connected thereto for controlling the pilot valve in response to the driven speed of the engine, and a differential pressure responsive means adapted to respond to the ratio of the air-fuel mixture supplied the engine when connected to the air inlet and fuel conduits re spectively to control the pilot valve in response to the air-fuel ratio.

17. Regulating means for regulating a fuel conduit for a combustion engine; said regulating means comprising a throttling valve having opposite end portions of different surface areas and an intermediate portion adapted to control said fuel conduit, a first conduit for connecting the end portion of smaller surface area With a source of uid pressure and independently of said end portion of larger surface area, a second conduit for connecting said end portion of larger surface area with said source of fluid pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve con trolling said opening to vary the pressure applied to the end portion of larger area to effect movement of the throttling valve, and a governor operatively connected to said pilot valve, said governor including a condition responsive means adapted to respond to `an operating condition of said engine when connected thereto for controlling the pilot valve in response. to such .condition.

18:. Regulating means for regulating a fuel conduit for a combustion engine; said regulating means. comprising a throttling valve having opposite end portions of different surface areas and an intermediate portion adapted to control said fuel conduit, a first conduit for connecting the end portion of smaller surface area with a source of fluid pressure and independently of said end portion of larger surface area, a second conduit for connecting said end portion of larger surface areawith said source of fluid pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve controlling said opening to vary the pressure applied to the end portion of larger area to effect movement of the throttling valve, an overspeed responsive mech'- anisrn adapted to respond to the driven speed of theV engine when connected thereto, valve means to controlv the supply of fluid pressure to position the throttling valve, and means controlled 'by the overspeed responsive mechanism independently of the governor to actuate the throttling valve l 1 so as to close the fuel conduit and to actuate the valve means so as to cut olf the fluid pressure for positioning the throttling valve when the speed of the engine exceeds a predetermined value.

19. Regulating means for regulating a fuel conduit for a combustion engine; said regulating means comprising a throttling valve having opposite end portions of different surface areas and an intermediate portion adapted to control said fuel conduit, a first conduit for connecting the end portion of smaller surface area with a source of fluid pressure and independently of said end portion of larger surface area, a second conduit for connecting said end portion of larger surface area with said source of fluid pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve controlling said opening to vary the pressure applied to the end portion of larger area to effect movement of the throttling valve, and an overspeed responsive means adapted to respond to the driven speed of the engine when connected thereto, said overspeed responsive means to actuate the throttling valve to close the fuel conduit when the speed of the engine exceeds a predetermined value.

20. Regulating means for regulating a fuel conduit for a combustion engine; said regulating means comprising a throttling valve having opposite end portions of different surface areas and an intermediate portion adapted to control said fuel conduit, a first conduit for connecting the end portion of smaller surface area with a source of fluid pressure and independently of said end portion of larger surface area, a second conduit for connecting said end portion of larger surface area with said source of fluid pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve controlling said opening to vary the pressure applied to the end portion of larger area to effect movement of the throttling valve, an overspeed responsive means adapted to respond to the driven speed of the engine when connected thereto, a latch mechanism controlled by said overspeed responsive means, a plunger releasably locked by said latch mechanism, and a spring effective upon release of said plunger to actuate said throttling valve to a position to close said fuel conduit and said plunger to a position to close at least one of the fluid pressure conduits.

21. Apparatus for use in controlling the fuel line of an engine for driving a generator, said apparatus comprising a throttling valve having opposite end portions of different surface areas and an intermediate portion adapted to control said fuel line, a first conduit for connecting the end portion of smaller surface area directly with a source of fluid pressure and independently of said end portion of larger surface area, a second conduit for connecting said end portion of larger surface area with said source of fluid pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve controlling said opening to vary the pressure applied to the end portion of larger area to effect movement of the throttling valve, and a governor including an electrical load responsive means :adapted to respond to the load applied to the generator for controlling the operation of said pilot valve.

22. Apparatus for use in controlling the fuel line of an engine for driving a generator, said apparatus comprising a throttling valve having opposite end portions of different surface areas and an intermediate portion adapted to control said fuel line, a first conduit for connecting the end portion of smaller surface area directly with a source of fluid pressure and independently of said end portion of larger surface area, a second conduit for connecting said end portion of larger surface area with said source of fluid pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve controlling said opening to vary the pressure applied to the end portion of larger area to effect movement of the throttling valve, and a governor including an electrical load responsive means adapted to respond to the load applied to the generator, speed responsive means adapted to respond to the driven speed of the engine, and differential pressure responsive means adapted to respond to the ratio of the air-fuel mixture supplied to the engine, and means operatively connecting the load, speed and differential pressure responsive means to said pilot valve for controlling the pilot valve and thereby the position of the throttling valve.

23. Apparatus for use in controlling the fuel line of an engine for driving a generator, said apparatus comprising a throttling valve having opposite end portions of different surface areas and an intermediate portion adapted to control said fuel line, a first conduit for connecting the end portion of smaller surface area directly with a source of fluid pressure and independently of said end portion of larger surface area. a second conduit for connecting said end portion of larger surface area with said source of uid pressure and having a restriction therein, an opening in said second conduit to drain, a pilot valve controlling said opening to vary the pressure applied to the end portion of larger area to effect movement of the throttling valve, speed responsive means adapted to respond to the driven speed of the engine when connected thereto for controlling the operation of said pilot valve, and an electromagnetic device adapted to respond to the electrical load on said generator when connected thereto for varying the speed setting of said governor.

\ JAMES EMIL BEVINS.

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